Even when the market goes down, any stock can still go against you. And while the common truism that short sellers can only ever make 100% on a position isn't quite right, it takes a certain skill to find companies that might be hiding something from investors.

But this doesn't stop traders from taking their best shot.

Recently, we've seen a ton of volatility in the stock market, but all of the major stock indexes are still higher year-to-date.

However, we were still able to find 30 stocks with market caps over $2 billion that investors are still betting against like crazy.

On the list, of course, is Herbalife, the company that hedge funder Bill Ackman has accused of being a pyramid scheme.

Also featured on the list is GoPro, the wearable camera company that went public in late June and has seen its stock just explode in the last several months.

The biggest theme of the list is Chinese internet companies. Alibaba may have been the marquee IPO of the year, but other internet-based companies out of China have been met with quite a bit of skepticism.

We ranked the stocks by short interest as a percentage of shares outstanding, going from the least shorted to the most.

Air Methods

Ticker: AIRM

Short interest: 23.4%

YTD return: -7.9%

Sector: Healthcare Services

Comment: In its most recent quarterly earnings report, the company reported revenue that increase 16% over the prior year to $258.5 million.

data from FinViz

Sunedison

Ticker: SUNE

Short interest: 24%

YTD return: 28%

Sector: Solar Energy

Comment: Sunedison, which makes solar panels and semiconductor materials, recently filed a confidential public offering for its yield vehicle focused on solar projects in Asia and Africa.

data from FinViz

Altisource Portfolio Solutions

Ticker: ASPS

Short interest: 24%

YTD return: -40%

Sector: Real Estate Services

Comment: The Luxembourg-based company provides debt collection services to mortgage lenders and is scheduled to report third quarter earnings on October 23.